安卓音乐播放器

关于安卓音乐播放器的MediaPlayer和Service联手实现播放网络音乐(只播放一首噢！！！)

首先来一个布局界面如下：

布局文件activity_main如下所示

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="50dp">

        <Button
            android:id="@+id/start"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="开始"
            android:textAllCaps="false"
            android:textSize="25sp" />

        <Button
            android:id="@+id/pause"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="暂停"
            android:textAllCaps="false"
            android:textSize="25sp" />

        <Button
            android:id="@+id/stop"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="关闭"
            android:textAllCaps="false"
            android:textSize="25sp" />
    </LinearLayout>
</LinearLayout>

接着MainActivity.java

package com.example.onlineplayer;

import android.app.Service;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.IBinder;

import java.io.IOException;

public class MyService extends Service {
    private MediaPlayer mediaPlayer;
    public static final String WEB_URL = "https://music-1253403821.cos.ap-beijing.myqcloud.com/%E8%AE%B8%E5%B5%A9%20-%20%E4%B8%83%E5%8F%B7%E5%85%AC%E5%9B%AD.mp3";

    @Override
    public void onDestroy() {
        //当activity生命周期销毁时调用
        //当播放器不为空和播放器正在播放
        if (mediaPlayer != null && mediaPlayer.isPlaying()) {
            //播放器停止
            mediaPlayer.stop();
            //停止后就被销毁了 所以需要让他准备
            //在这里释放资源 优化内存
            mediaPlayer.release();
            mediaPlayer = null;
        }
        super.onDestroy();
    }


    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    private void startMusic() {
        mediaPlayer = new MediaPlayer();
            try {
                mediaPlayer.setDataSource(WEB_URL);
                mediaPlayer.prepareAsync();
                mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
                    @Override
                    public void onPrepared(MediaPlayer mp) {
                        mediaPlayer.start();
                    }
                });
            } catch (IOException e) {
                e.printStackTrace();

        }
    }

    private void pauseMusic() {
        mediaPlayer.pause();
    }

    private void stopMusic() {
        mediaPlayer.stop();
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        String action = intent.getStringExtra("action");
        if ("start".equals(action)) {
            startMusic();
        } else if ("pause".equals(action)) {
            pauseMusic();
        } else if ("stop".equals(action)) {
            stopMusic();
        }

        return super.onStartCommand(intent, flags, startId);
    }

下面是Service.java

package com.example.onlineplayer;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;

/***
 * 演示MediaPlayer播放网络音频
 */
public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private Button start;
    private Button pause;
    private Button stop;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        init();
    }


    private void init() {
        start = findViewById(R.id.start);
        pause = findViewById(R.id.pause);
        stop = findViewById(R.id.stop);
        start.setOnClickListener(this);
        pause.setOnClickListener(this);
        stop.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        Intent intent = new Intent(this, MyService.class);
        switch (v.getId()) {
            case R.id.start:
                intent.putExtra("action", "start");
                startService(intent);
                break;
            case R.id.pause:
                intent.putExtra("action", "pause");
                startService(intent);
                break;
            case R.id.stop:
                intent.putExtra("action", "stop");
                startService(intent);
                break;
        }
    }

}

最后在功能清单文件里注册service和网络权限

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.onlineplayer">

    <uses-permission android:name="android.permission.INTERNET" />
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <service android:name=".MyService"/>
    </application>
</manifest>